Table 3. Adjusted Regression Coefficients (Hierarchical Linear Modeling) for Pain Severity and Physical Function
SF-12 Physical FunctioningP ValueBPI Pain SeverityP Value
Estimate95% Confidence IntervalEstimate95% Confidence Interval
Treatment period3.034.811.24<.001−0.71−0.40−1.03<.001
Posttreatment period2.614.470.77.006−0.410.77−1.59.496
Time (weeks centered around baseline)−0.04−0.130.04.117
Time × treatment period−0.020.04−0.08.554
Time × after treatment period−0.010.07−0.08.854
Site.44.744
    Site A−0.55−3.682.580.12−0.360.60
    Site B2.00−1.505.50−0.20−0.740.35
    Site C−0.66−3.452.130.00−0.430.43
    Site DReferenceReferenceReferenceReferenceReferenceReference
CPGS disability score−0.14−0.18−0.10<.0010.040.030.04<.001
Treatments received0.230.080.38.003
Age−0.18−0.26−0.10<.001
Medicaid0.500.850.15.005
  • BPI, Brief Pain Inventory; CPGS, Chronic Pain Grading Scale; SF12, 12-item Short Form.